Blender Mesh: Which UV Unwrapping Approach
Normally I wouldn't use it, because I mostly do organic modeling, but I'm thinking for what you are doing, Smart UV Project might work very well. It's under the UV Mapping menu (press U in Edit Mode to bring it up). It tries to automatically unwrap your mesh without you creating any seams first. One nice thing about it is that even if you ignore all the settings and just press OK, the settings menu remains active afterwards, so you can keep tweaking the values in the fields and see updated changes to the UV map. This is great because some of those settings would be hard to understand exactly what they do based only on their descriptions.